Title: Magnetorheological polishing of rapid tool parts

Authors: John O'Brien, Gerard Ryder

Addresses: Department of Mechanical Engineering, ITT Dublin, Dublin 24, Ireland. ' Department of Mechanical Engineering, ITT Dublin, Dublin 24, Ireland

Abstract: Magnetorheological (MR) polishing is a relatively new finishing process that uses an electromagnetic field to produce a magnetic abrasive brush. The brush consists of a ferromagnetic material, an abrasive material and oil, which is used primarily as a binder. When the brush is brought into contact with the surface of the part and there is relative motion between the two, polishing occurs. The magnetic field strength, the make up of the fluid, the relative motion speed, the working gap between the electromagnet and the workpiece surface and the duration of polishing can all potentially affect the surface finish and the material removal rate. Preliminary tests have shown that the polishing of aluminium and Rapid Tooling (RT) samples is possible. The polishing of RT samples present a different challenge because of their magnetic characteristics. Results have shown that the working gap and the electromagnet voltage are the two main parameters that affect the surface finish Ra value of the aluminium samples. The composition of the magnetic brush, although not affecting the Ra value has a major influence on the polishing action produced. This can vary from a loose abrasive type finish to a fixed abrasive finish.

Keywords: RT; rapid tooling; MR polishing; magnetorheological polishing; aluminium polishing; working gap; magnetic brush; electromagnet voltage; surface finish; surface roughness.

DOI: 10.1504/IJCMSSE.2009.024930

International Journal of Computational Materials Science and Surface Engineering, 2009 Vol.2 No.1/2, pp.118 - 127

Published online: 04 May 2009 *

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